<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>下拉菜单</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        li {
            list-style-type: none;
        }

        a {
            text-decoration: none;
            font-size: 14px;
        }

        .nav {
            margin: 100px;
        }

        .nav li {
            position: relative;
            float: left;
            width: 80px;
            height: 41px;
            text-align: center;
        }

        .nav li a {
            display: block;
            width: 100%;
            height: 100%;
            line-height: 41px;
            color: #333;
        }

        .nav li a:hover {
            background-color: #eee;
        }

        .nav ul {
            display: none;
            position: absolute;
            top: 41px;
            left: 0;
            width: 100%;
            border-left: 1px solid #FECC5B;
            border-right: 1px solid #FECC5B;
        }

        .nav ul li {
            border-bottom: 1px solid #FECC5B;
        }

        .nav ul li a:hover {
            background-color: #FFF5DA;
        }
    </style>
    <script src="js/jquery.min.js"></script>
    <script>
        $(function () {
            $(".nav li").mouseover(function () {
                $(this).children("ul").show();
            })
            $(".nav li").mouseout(function () {
                $(this).children("ul").hide();
            })


        })


    </script>
</head>
<body>
<ul class="nav">
    <li>
        <a href="#">微博</a>
        <ul>
            <li>
                <a href="">私信</a>
            </li>
            <li>
                <a href="">评论</a>
            </li>
            <li>
                <a href="">@我</a>
            </li>
        </ul>
    </li>
    <li>
        <a href="#">微信</a>
        <ul>
            <li>
                <a href="">私信</a>
            </li>
            <li>
                <a href="">评论</a>
            </li>
            <li>
                <a href="">@我</a>
            </li>
        </ul>
    </li>
</ul>

</body>
</html>